feat(providers): modernize CLOVA Studio chat and embeddings (#12277)

Validado em lote numa worktree combinada com #12524, #12538, #12277 e #12367 sobre o tip de release/v3.8.51: os quatro boardaram sem conflito (áreas disjuntas — zai-web, nvidia, clova, cursor/devin/fable). typecheck:core limpo, check:provider-consistency OK (272 entradas REGISTRY, 355 providers canônicos), check:known-symbols OK, e 305/305 nos testes tocados pelos quatro PRs. Os IDs de modelo adicionados foram conferidos individualmente. Obrigado, @backryun.

scripts/check/check-known-symbols.ts

@@ -211,6 +211,8 @@ export const KNOWN_TRANSLATOR_PAIRS: readonly string[] = [
   "antigravity:openai",
   "claude:gemini",
   "claude:openai",
+  // Naver CLOVA Studio Chat Completions v3 (native envelope, model in URL path).
+  "clova:openai",
   "cursor:openai",
   "gemini:claude",
   "gemini:openai",
@@ -218,6 +220,7 @@ export const KNOWN_TRANSLATOR_PAIRS: readonly string[] = [
   "openai-responses:openai",
   "openai:antigravity",
   "openai:claude",
+  "openai:clova",
   "openai:cursor",
   "openai:gemini",
   "openai:kiro",